First Commit

externals/oaknut/include/oaknut/feature_detection/feature_detection_freebsd.hpp

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+// SPDX-FileCopyrightText: Copyright (c) 2023 merryhime <https://mary.rs>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <cstdint>
+#include <optional>
+
+#include <sys/auxv.h>
+#include <sys/param.h>
+
+#include "oaknut/feature_detection/cpu_feature.hpp"
+#include "oaknut/feature_detection/feature_detection_hwcaps.hpp"
+#include "oaknut/feature_detection/id_registers.hpp"
+#include "oaknut/feature_detection/read_id_registers_directly.hpp"
+
+#ifndef AT_HWCAP
+#    define AT_HWCAP 16
+#endif
+#ifndef AT_HWCAP2
+#    define AT_HWCAP2 26
+#endif
+
+#if __FreeBSD_version < 1300114
+#    error "Incompatible ABI change (incorrect HWCAP definitions on earlier FreeBSD versions)"
+#endif
+
+namespace oaknut {
+
+namespace detail {
+
+inline unsigned long getauxval(int aux)
+{
+    unsigned long result = 0;
+    if (::elf_aux_info(aux, &result, static_cast<int>(sizeof result)) == 0) {
+        return result;
+    }
+    return 0;
+}
+
+}  // namespace detail
+
+inline CpuFeatures detect_features_via_hwcap()
+{
+    const unsigned long hwcap = detail::getauxval(AT_HWCAP);
+    const unsigned long hwcap2 = detail::getauxval(AT_HWCAP2);
+    return detect_features_via_hwcap(hwcap, hwcap2);
+}
+
+inline std::optional<id::IdRegisters> read_id_registers()
+{
+    // HWCAP_CPUID is falsely not set on many FreeBSD kernel versions,
+    // so we don't bother checking it.
+    return id::read_id_registers_directly();
+}
+
+inline CpuFeatures detect_features()
+{
+    return detect_features_via_hwcap();
+}
+
+}  // namespace oaknut